Status in 2020 and request for beamtime in 2021 for CERN NA63

In the NA63 experiment of April 2018 reliable data was taken for 40 and 80 GeV electrons and positrons aligned to the $\langle100\rangle$ axis of a diamond crystal of thickness 1.5 mm, as well as for 40 and 80 GeV electrons on a 1.0 mm thick diamond aligned to the $\langle100\rangle$ axis. A paper has been submitted to Phys.\ Rev.\ D, and has received favourable referee comments. For the 2017 data, a paper has been published in Phys.\ Rev.\ Research in 2019, and our experimental findings have inspired another paper published in Phys.\ Rev.\ Lett.\ \\ For the year 2021 we request 2 weeks of beamtime in the SPS H4 to do a measurement of trident production, $e^-\rightarrow e^-e^+e^-$, in strong crystalline fields. This process is closely related to the production of muon pairs, $e^-\rightarrow e^-\mu^+\mu^-$, and single crystals may prove to be an attractive source to obtain muons of high intensity and small emittance, as required for a muon collider. The trident results obtained in 2009, and published in 2010, are strongly at odds with theory (factor 3-4 discrepancy). Since then we have acquired and have been using MIMOSA-26 position-sensitive detectors with a resolution about a factor 40 higher than the drift chambers used in 2009, and now with true multi-hit capability, a significant advantage when looking for trident events. Thus we have substantial improvements in our equipment that enable a much more precise measurement.